// AJAX

function sendAJAX(url) {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest()
    xhr.open('GET', url)
    xhr.send()

    xhr.onreadystatechange = function(){
      if(xhr.readyState === 4) {
        if(xhr.status >=200 && xhr.status < 300) resolve(xhr.response)
        else reject(xhr.err)
      }
    }
  })
}

